expandable RAID-Z

*** 1224,1239 ****
--- 1224,1247 ----
                  vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
          else
                  vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
  }
  
+ static uint8_t
+ vdev_raidz_grid(vdev_t *vd)
+ {
+         ASSERT(vd->vdev_nparity - 1 <= 1);
+         return (((vd->vdev_nparity - 1) << 6) | vd->vdev_children);
+ }
+ 
  vdev_ops_t vdev_raidz_ops = {
          vdev_raidz_open,
          vdev_raidz_close,
          NULL,
          vdev_raidz_asize,
          vdev_raidz_io_start,
          vdev_raidz_io_done,
          vdev_raidz_state_change,
+         vdev_raidz_grid,
          VDEV_TYPE_RAIDZ,        /* name of this vdev type */
          B_FALSE                 /* not a leaf vdev */
  };